Dyslexia is a form of reading disability that affects a significant proportion of children. Efforts to explain dyslexia have identified neural and chromosomal risk factors for dyslexia and the deficits related to dyslexia. The chromosomal markers implicated in dyslexia include regions related to a variety of developmental abnormalities. A neural risk factor related to dyslexia, Heschl's gyrus duplication, may be one aspect of the phenotypic expression of genes within the regions identified as chromosomal markers for dyslexia. A long term goal of this research will be to perform linkage analysis for Heschl's gyrus duplication. However, a pedigree for Heschl's gyrus duplication must first be developed in order to establish the proper linkage analysis approach. This proposal is designed to collect pedigrees for a Heschl's gyrus duplication and then identify chromosomal markers for the duplication. On a broader level, this proposal will combine two areas of biological research directed towards developing an understanding of the mechanisms that produce dyslexia.